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Pyrene-functionalized Ru nanoparticles were synthesized by olefin metathesis reactions of carbene-stabilized Ru nanoparficles with 1-vinylpyrene and 1-allylpyrene (the resulting particles were denoted as Ru=VPy and Ru=APy, respectively) and examined as sensitive chemosensors for the detection of nitroaromatic compounds, such as 2,4,6-trinitrotoluene (TNT), 2,4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT), 1-chloro-nitrobenzene (CNB), and nitrobenzene (NB), by their effective quenching of the nanoparticle fluorescence. It was found that the detection sensitivity increased with increasing nitration of the molecules. Additionally, in comparison to monomeric pyrene derivatives, both Ru=VPy and Ru=APy nanoparticles exhibited markedly enhanced performance in the detection of nitroaromatic explosives, most probably as a result of the enhanced collision frequency between the fluorophores and the quencher molecules. Furthermore, Ru=VPy nanoparticles displayed much higher sensitivity (down to the uanomolar regime for TNT) than Ru=APy in the detection of these nitroaromatic explosives, which was ascribed to the extended intraparticle conjugation that provided efficient pathways for energy/electron transfer and consequently amplified the analyte binding events. 10.1021/ac902394s

A series of unsymmetrical bi- and tetrathiophenes are synthesized with bipyridine and phosphonic acid functional groups. The variation in oligothiophene length and bipyridine substitution position has allowed comparison of the effect of the variables on electronic properties.

A pure ruthenium hydride complex with N-heterocyclic carbene ligand was efficiently generated from the reaction of a second-generation Grubbs ruthenium catalyst with vinyloxytrimethylsilane and unambiguously characterized. This ruthenium hydride complex showed high catalytic activity for the selective isomerization of terminal olefin and for the cycloisomerization of 1,6-dienes.

The electron-rich cyclopentadienylruthenium complex CpRuCl(PPh3)(sub 2) has turned out to be an efficient catalyst for the cyclopropanation of a wide range of norbornenes and norbornadienes with propargylic carboxylates. An efficient cyclopropanation of cyclobutenes is demonstrated, providing the strained bicyclo[2.1.0(super 1,3)]pentane framework.

The rhodium(III) complex mer,cis-[RhCl3(PPh2py-P,N)(PPh2py-P)] (PPh2py = diphenyl (2-pyridyl)phosphine) is prepared from RhCl3.3H2O and PPh2py and converted to the trans,cis-[RhCl3(PPh2py-P,N)2]PF6 in acetone solution by treatment with Ag(super +) and PF6(super -). The (super 31)P chemical shifts for chelating PPh2py-P,N depend on the Ru-P bond lengths.

Differences in the relative energies of the interconfigurational (IC) transitions for the fully oxidized (+6) states of the osmium systems demonstrate that stereochemical effects lead to fundamental changes in the energy levels of the metal-based dpi orbitals, which are split by spin-orbit coupling and ligand-field asymmetry. An increase in the separation between the IC bands as BL is varied reflects the increase in the degree of electronic coupling through the series of ruthenium and osmium complexes.

Ambipolar charge transport confined to a self-assembled monolayer of a heteroleptic ruthenium complex anchored on the surface of mesoscopic oxides was observed. The bipyridyl ligands of the Ru-complex transport electrons, while the NCS group plays an important role in mediating surface confined hole percolation.

Ambipolar charge transport confined to a self-assembled monolayer of a heteroleptic ruthenium complex anchored on the surface of mesoscopic oxides was observed. The bipyridyl ligands of the Ru-complex transport electrons, while the NCS group plays an important role in mediating surface confined hole percolation.

A series of mixed-ligand 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen) rhenium(I) dicarbonyl complexes are synthesized, which includes a new class of the type cis-[Re(CO)(sub 2)(P-P)(N-N)](super +) (where P-P is a chelating diphosphine and N-N is a chelating polypyridine ligand). The properties of these new complexes vary with the net donor ability of the ligands in the coordination sphere and lifetimes and quantum yields of the bipyridine complexes encompass a broad range.

Thiophene containing hybrids based on the bent conjugated backbone of a rigid ditopic ligand, the dimeric moiety 3,4-dibutyl-2,5-bis{5'-[(3,4-dibutylthien-2-ylethynyl)-2,2'-bipyridin-5-yl]ethynyl}-thiophene (TBTBT) and side decorated with Re(I), Ru(II) and Os(II) metal based units are described. Upon photoexcitation of the heterometallic species, energy transfer takes place via the connecting dimeric ligand.

A planar structure of an anion cluster I(super -).(H(sub 2)O)(sub 6) in a 3D supramolecular complex [Ru(bpy)(sub 3)](sub 2)[I.(H(sub 2)O)(sub 6)Fe(CN)(sub 6).H(sub 2)O] was determined by single crystal X-ray analysis. In the supramolecule, the anion cluster I(super -).(H(sub 2)O)(sub 6), together with the anion [Fe(CN)(sub 6).H(sub 2)O](super 2-) acts as a 3D crystal host, and the [Ru(bpy)(sub 3)](super 2+) cations, as the guest molecule, occupy the vacancies of the 3D host framework.

A static electron-transfer quenching mechanism for iodide photooxidation with visible light is demonstrated. The spectroscopic data suggests that the Ru(II)-iodide adducts arise from interactions between iodide and diimine ligand(s) as well as ion pairing.

Development of ruthenacarborane complex [3,3,3-(CO)(sub 3-)closo-3,1,2-RuC(sub 2)B(sub 9)H(sub 11)] is demonstrated by introduction of chelating N-donor ligands such as 2.2'-bipyridyl and the electronic structure of new complexes are examined. Photophysical analysis revealed no substantial luminescent activity, but the complexes are electrochemically active, undergoing sequential one-electron reductions, the second of which likely precipitating a ligand displacement.

The analysis and characterization of Ru(II) compounds are described. It is found that these compounds exhibited a single quasi-reversible Ru(super III)/(super II) wave and legand-localized waves corresponding to the sequential reduction of the dimine ligans

Photocurrent measurements are made on nanocrystalline TiO2 surfaces derivatized by adsorption of a catalyst precursor or chromophore, and on surfaces containing both complexes. The experiments are carried out with the I(sub 3)(super -)/I(super -) or quinone/hydroquinone (Q/H2Q) relays in propylene carbonate, propylene carbonate-water mixtures, and acetonitrile-water mixtures.

Synthesis of two neutral diruthenium complexes and one anionic diruthenium complex, Ru2(dpf)4(NO), Ru(dpf)4(NO)2, and [Ru(dpf)4(NO)](super -), where dpf is diphenylformamidinate anion, was conducted and characterized as to their electrochemical and spectroscopic properties. Results reveals the presence of a strong interaction between No and Co across the metal-metal bond.

A combined experimental and computational study of polynuclear [Ru(sub n)(TPPZ)(subn+1)](super(2n+) complexes of interest in the field of photoactive polymers are reported. The complexes with n = 1,2,3 and n>5 are synthesized and spectroscopically characterized.

Investigations on the ruthenium porphyrin-catalyzed intramolecular amidation of sulfamate esters and of the first intramolecular aziridation of unsaturated sulfonamides are reported. Bicyclic aziridines up to 87% yield with 100% substrate conversion and high turnover were produced.

The dynamics of metal-to-ligand charge transfer (MLCT) in a cis-bis(4'4-dicarboxy-2,2'-bipyridine)-bis(isothiocyanato)ruthenium(II) dye (N3) are compared for the free dye in solution and the dye absorbed on the surface of the TiO2 nanoparticles from resonance Raman spectroscopy. The 544-nm MLCT absorption band of N3 absorbed on TiO2 is slightly blue-shifted from that of the free N3, indicating a weak electronic coupling between N3 and TiO2.

Single molecules detected through the phosphorescence emission of their triplet states, and the emission of the triplet state of single molecules of PtOBCP and Ru(dpp)3Cl(sub 2) are reported. Each molecule was found to have its own characteristic quenching rate by oxygen, and the distribution of the rates was measured for Ru(dpp)3Cl(sub 2) on a quartz surface.

The heterolytic cleavage of H2 is regarded as a key step in the metalloenzymatic reactions of hydrogenases, the actives sites of which consist of the sulfur-bridged Fe/Fe and Fe/Ni dinuclear centers. Based on the experimental results, the mechanism of the heterocyclic H2 activation and the reverse H2 evolution reactions are discussed.

The atomic structure of RuO2.xH2O as a function of water content from x=0.84 to 0.002 using X-ray diffraction and atomic pair density function is studied. The result reveals that RuO2.xH2O is a composite of anhydrous rutile-like RuO2 nanocrystals dispersed by boundaries of structural water associated with Ru-O.

The IR spectroscopy is use to investigate the interactions of nitric oxide gas with thin layers of Fe(super ll)(TPP) and Ru(super ll)(TPP), obtained by sublimation onto low-temperature substrate (77 K). It was found that purified nitrogen oxide does not react with Fe(TPP)(NO) to give Fe(TPP)(NO)(NO2), however, this interaction led only to the formation of unstable trans-dinitrosyl complex Fe(TPP)-(NO)2.

An ultrafast spectroscopic investigation of the photoinduced energy migration dynamics that take place within a supramolecular assembly consisting of 20 Ru(II) and/or Os(II) polypyridyl coordination complexes linked together through a polystyrene backbone is described. The results demonstrate that the Ru(II) derivatized polymers act as efficient antennas for collecting visible light and transferring its energy along the polymer backbone.

The reaction of the dihydride [Ru(super II)(H)(sub 2)(CO)(PPh3)(sub 3)] with excess azo-2,2'-bipyridine (abp) in boiling dry benzene has afforded the diradical bischelate [Ru(super II)(abp(super .-))(sub 2)(CO)(PPH3)] and the hydridic monochelate monoradical [Ru(super II)(abp(super .-))(H)(CO)(PPH3)(sub 2)]. The diradical bischelate displays strong metal-mediated antiferromagnetism, and upon oxidation to the monoradical the unpaired electron with approximately 40 percent azo pi(super star)-character gets localized in one of the chelate rings.

Visible light-driven intermolecular electron transfer observed from a reduced species Ru[(bpy).sub.3.sup.+] to bioinspired [2Fe2S] model complexes of the iron-only hydrogenase active site is reported. The results indicate that Ru[(bpy).sub.3.sup.+] could act as a photoactive functional model of the [4Fe4S] cluster playing the role of an electron-transfer relay.

The nature of the Ru-S bond in the parent thiolato complexes and mono- (sulfenato) and bis- (sulfinato) oxygenated species including the affect of substituents on the sulfur and arene are compared. Sulfur K-edge XAS results have shown that [S.sub.3p] donation into the [Ru.sub.4d] manifold has depended on the oxidation state of the sulfur atom, whereas Ru K-edge data has shown little change at the metal center, and the DFT results have allowed a more detailed analysis of the electronic contributions to the Ru-S bond.

The catalysis mechanism and kinetic isotope effect (KIE) which occur through a rapid transfer of a hydride from the ruthenium and a proton from the amine on the trans-dihydride complex trans-Ru[H.sub.2](N[H.sub.2]C[Me.sub.2]C[Me.sub.2]N[H.sub.2])((R)-binap) to the carbonyl of the ketone to give the product alcohol and a hydrido-amido intermediate RuH(NHCMe2CMe2NH2)((R)-binap) is described. The significance of the results obtained relative to the KIE of RuH(NHC[Me.sub.2]C[Me.sub.2]N[H.sub.2])((R)-binap) for the hydrogenation/deuteriation of acetophenone catalyzed by trans-RuH([eta]1-B[H.sub.4])((S)-tolbinap)((S,S)-dpen) in basic isopropanol/isopropanol-[d.sub.8] is also discussed.

The article describes the synthesis and characterization of a series of ionic Ru(II) arene Cp* sandwich complexes. The results from screening for cytotoxicity against a range of human tumor cell lines and normal human cells reveal the complexes to exhibit promising anticancer activity that varies with changes in the arene ligand and the anionic counterion.

The first example for an endohedral transition-metal atom (Ru) sequestered in a seven-coordinate surrounding of rare-earth metal atoms (Pr) is found for {Ru[Pr.sub.3]}[Cl.sub.3]. The monocapped trigonal prisms of Pr atoms have shared two rectangular faces and intracluster bonding is dominated by Ru-Pr bonding with very little Ru-Ru bonding.

Ruthenium(II) complexes bearing pterins are studied using spectroscopic methods, X-ray crystallography and electrochemical measurements. These complexes show reversible proton-coupled electron transfer (PCET) to form ruthenium-coordinated neutral monohydropterin radicals as intermediates of PCET process.

A study reveals that a bis(disulfide)-bridged Ru[Mo.sub.3][S.sub.4] double-cubane cluster is readily available from cluster [[(Cp*Mo).sub.3][([mu.sub.3]-S).sub.4]Ru[H.sub.2](PP[h.sub.3])][P[F.sub.6]] and [S.sub.8]. The reactions of such double-cubane cluster with [M(PP[h.sub.3]).sub.4] (M=Pd, Pt) give arise to the formation of a new family of nona- or decanuclear mixed-metal clusters, with two Ru[Mo.sub.3][S.sub.4] cubane units.

The syntheses of templated assembly of [[Ru.sup.II][(bpy).sub.3]]- [[Pd.sup.II.sub.2][(ox).sub.3]], Pd2 and [[Ru.sup.II][(bpy).sub.3]][[Pd.sup.II][Mn.sup.II][(ox).sub.3]], PdMn are described. X-ray absorption spectroscopy results revel an unusual 6-fold oxygen environment around the Pd(II) atoms and due to this palladium(II) has a triplet (S=1) ground state.

The synthesis and characterization of a series of CpRu and Cp*Ru hydride and related complexes containing either the phosphinoamine ligand dippae (1,2-bis(diisopropylphosphinoamino)ethane) or the enantiopure (R,R)-dippach ((R,R)-1,2-bis(diisopropylphosphinoamino)cyclohexane) are presented. The proton-transfer reaction of the complexes is studied by variable-temperature (VT)-NMR spectroscopy.

The flow cytometry, traditionally used to examine organic fluorophores is exploited to provide statistics on the uptake of ruthenium complexes into HeLa cells. A powerful complement in the design of metal complexes for biological application is provided using a range of metal complexes.

The experimental and theoretical studies on the electronic structures of a series of ruthenium complexes [Ru(OAc)-(dioxolene)(terpy)] having various substituents on the dioxolene ligand is described. An increase in the number of Cl atoms in the dioxolene ligand results in an increase of the positive charge of Ru.

A study describes a new strategy for the noncovalent immobilization of ruthenium-based olefin metathesis catalyst that relies on electrostatic binding. The solid-phase bound catalyst shows very good chemical reactivity and good recyclability, and on glass-polymer composite Raschig rings can be applied in combinatorial chemistry and high-throughput screening to give products of high purity and of low ruthenium contamination.

An example of a 16-electron, dicatioinic elongated dihydrogen complex of ruthenium that is stabilized by an agostic Ru...H-C interaction is reported. The hydride and dihydrogen complexes are stabilized via agostic interaction of the ortho C-H fragment of the phenyl ring on the benzyl group.

The electronic properties of a zeroth-order dendrimer which was formed using a tridentate bridging ligand, 2,4,6-tri-4-pyridyly-S-triazine is explored using cyclic voltammetry. The dendrimer is seen to exhibit an unusual and complex series of electronic behaviors at room temperature, including intramolecular cluster-to-bridging-ligand charge transfer, gated electron transfer, and dynamic exchange on the IR time scale.

A new hybrid complex of polypyridyl ruthenium(II) and tetra(pyridy)porphyrin, [[{Ru(bpy)(trpy)}4(H2Py4P)].sup.3+], where (bpy = 2,2'-bipyridine, trpy = (2,2':6',2'-tetridine and H2Py4P = 5, 10, 15, 20-tetra(4-pyridyl)porphyrin)) is prepared. The hybrid complex shows both porphyrin and ruthenium phosphorescence, in addition to the porphyrin fluorescence.

Oxidative cyclodehydrogenation is an important process in the formation of the new graphene, N-1/2HSB, which results from the FeCl3-catalyzed oxidative cyclodehydrogenation of 1,2-dipyrimidyl-3,4,5,6-tetra-(4-tert-butylphenyl)benzene. The new ligand N-1/2HSB, its Ru(II) complexes and also the half-cyclized N-1/2HSB are characterized by (super 1)H, NMR, infra-red (IR), ESI-MS, and accurate aromatic ligands.

A series of dinuclear homometallic ruthenium and osmium complexes containing p-polyphenylene units as spacers are synthesized and investigated. The time-resolved emission and transient adsorption spectroscopy reveal that in the excited state the electronic density is delocalized over the p-phenylene spacers.

The first series of ruthenium compounds containing both acetylide and bipridyl ligands are prepared. The ruthenium(II)- acetylide compounds are readily oxidized to ruthenium-(III), changing color as a MLCT transition is replaced by a LMCT transition.

The use of ruthenium(II) (Ru(II)) centers in conjuction with simple monodentate ligands such as the pyridyl group, to synthesize symmetrical or asymmetrical catenanes is described. The coordination properties of the 1,10-phenanthroline (phen)/bis-pyridine ligand with Ru(II) are also investigated.

It is reported that disulfur ligands bridging two metal atoms have three possible coordination modes: (n(super 1), n(super 1)), (n(super 1), n(super 2), and (n(super 2), n(super 2). Chemical and electrochemical redox are studied in pursuit of a more general view for such redox-associated behavior of disulfide ligands.

The synthesis and characterization of a neutral trinuclear heterobimetallic cyano-bridged Ru(II)/Pt(II) complex, cis-Ru(phen)2-[CN-Pt(DMSO)Cl2]2 (phen =1, 10-phenanthroline) (1), as a chemodosimetric ensemble(super 8) for sulfhydryl-containing amino acids and peptides is reported. Metal-to-ligand charge transfer (MLCT) emission of cis-[Ru(phen)2(CN)2] is quenched upon coordination of the cyano moieties by the electron-accepting Pt(DMSO)Cl2 moieties.